Expressão diferencial de proteínas do fungo Conidiobolus lamprauges cultivado em diferentes temperaturas / Differential expression of protein of the fungus Conidiobolus lamprauges cultivated at different temperatures

Para sobreviverem na temperatura corpórea de seu hospedeiro, os fungos patogênicos têm desenvolvido mecanismos moleculares importantes, como a expressão de proteínas relacionadas ao crescimento em altas temperaturas. Assim, o objetivo deste trabalho foi analisar o crescimento in vitro de Conidiobolus lamprauges em diferentes temperaturas e comparar o perfil de proteínas expressas através de eletroforese bidimensional (2D), em duas temperaturas distintas, sendo uma considerada baixa (28°C) e alta (37°C). Para análise do crescimento em diferentes temperaturas, cinco isolados de C. lamprauges, oriundos de ovinos doentes, foram incubados a 20, 25, 30, 35 e 40°C e o crescimento radial foi medido a cada 24 horas. Para análise da expressão diferencial, realizou-se a extração de proteínas do fungo cultivado a 28°C e a 37°C por 48 horas. A média de crescimento radial dos isolados foi diferente nas temperaturas analisadas, sendo 35°C a melhor temperatura para crescimento em todas as amostras. A temperatura ótima ajustada variou entre 33,3°C a 34,8°C. Os limites inferior e superior de inibição de crescimento foram 18°C e 42°C, respectivamente. Na análise da expressão diferencial, foram encontrados 16 spots diferencialmente expressos, sete (7/16) estavam com expressão diminuída e nove (9/16) com expressão aumentada a 37°C, quando comparado a 28°C. Além disso, oito spots estavam presentes apenas a 28°C e seis a 37°C. Sugere-se que C. lamprauges produza um perfil de proteínas relacionadas à termorregulação desencadeado pela alta temperatura do hospedeiro.

To survive at the body temperature of their hosts, pathogenic fungi have developed important molecular mechanisms, such as protein expression associated with growth at high temperatures. Thus, the aim of this study was to analyze the in vitro growth of Conidiobolus lamprauges at different temperatures and compare proteins expressed by two-dimensional electrophoresis (2D), for the pathogen cultivated at low (28°C) and high (37°C) temperatures. For the analysis of growth temperatures, five isolates of C. lamprauges from sick sheep were incubated at 20, 25, 30, 35 and 40°C and radial growth was measured every 24 hours. For the analysis of differential expression, protein extraction and two-dimensional polyacrylamide gel electrophoresis were performed with C. lamprauges cultivated at 28°C and 37°C for 48 hours. The average radial growth was different at the temperatures tested, and 35°C was found to be the best growth temperature for all isolates. The optimum adjusted temperature ranged between 33.3°C and 34.8°C. The upper and lower limits of growth inhibition were 18°C and 42°C, respectively. Upon expression analysis, a total of 16 spots were differentially expressed, seven (7/16) proteins were downregulated and nine (9/16) were over-expressed at 37ºC compared to 28°C. In addition, eight spots were present only at 28ºC and six were present only at 37ºC. It is suggested that C. lamprauges produces a profile of proteins that is related to thermoregulation triggered by the high temperature of the host.

Comparison of simple sequence repeats in 19 Archaea

All organisms that have been studied until now have been found to have differential distribution of simple sequence repeats (SSRs), with more SSRs in intergenic than in coding sequences. SSR distribution was investigated in Archaea genomes where complete chromosome sequences of 19 Archaea were analyzed with the program SPUTNIK to find di- to penta-nucleotide repeats. The number of repeats was determined for the complete chromosome sequences and for the coding and non-coding sequences. Different from what has been found for other groups of organisms, there is an abundance of SSRs in coding regions of the genome of some Archaea. Dinucleotide repeats were rare and CG repeats were found in only two Archaea. In general, trinucleotide repeats are the most abundant SSR motifs; however, pentanucleotide repeats are abundant in some Archaea. Some of the tetranucleotide and pentanucleotide repeat motifs are organism specific. In general, repeats are short and CG-rich repeats are present in Archaea having a CG-rich genome. Among the 19 Archaea, SSR density was not correlated with genome size or with optimum growth temperature. Pentanucleotide density had an inverse correlation with the CG content of the genome.

Abdominal pigmentation and growth temperature in Indian Drosophila melanogaster : Evidence for genotype-environment interaction.

Phenotypic variability for abdominal pigmentation in females of an Indian natural population of Drosophila melanogaster was studied using isofemale lines and by rearing the larvae and pupae at 4 different temperatures ranging from 20–30°C. The dark pigmented area was found to increase in all the three segments when the growth temperature decreases. A significant positive correlation was detected for the occurrence of dark pigmentation in the 5th and 6th segments in each growth temperature but for other comparisons the correlation was not regular. Analysis of variance (ANOVA) was carried out both for individual segments over different growth temperatures and also for each temperature over the three abdominal segments and in all cases found to be statistically significant. The results are quite different from the earlier observation in French Drosophila melanogaster and suggest that genes controlling pigmentation are temperature dependent; temperature could affect post-transitional events involved in pigmentation. The present findings also clearly indicate that significant genotype-environment interaction exists, responsible for the production of desired phenotype at the opportune moment during the life span of a species.